1. Field of the Invention
This invention relates to improvements in clinometers. More specifically, it refers to an improved plumb indicating device for facilitating plumbing of vertical surfaces such as piles.
2. Description of the Prior Art
The plumbing of vertical piles is usually accomplished by the conventional plumb bob and line. The plumb bob has certain inherent disadvantages in that it must be in a motionless position before an accurate sighting can be made. If strong winds are present, the plumb bob must be sheltered to enable it to assume a motionless position. A further disadvantage of the plumb bob is that if the surface is uneven at intermediate points, e.g., driven piles tend to distort from straightness, or if it has projections, the plumb line must be positioned away from their distortions in order to hang in a vertical position.
An early plumb indicating device U.S. Pat. No. 2,807,888 to Thomas provided for lateral projections at each of its ends to bridge distortions in a vertical surface to be plumbed. This device however, is not provided with interchangeable extension members, nor does it provide for a plurality of scale plates for measuring the degree of plumbness of a surface. The present invention is also distinguishable from the Thomas reference in that it is provided with stand-off projecting members that have longer surface engaging portions to provide for a sturdier, more solid engagement between the device and the vertical surface to be plumbed. The present invention additionally provides for the attachment of scale plates to the extension members, and a compass may be attached to the top of the level bar or extension members for determining if any rotation of a pile has been realized.
U.S. Pat. No. 2,834,118 to Jackson discloses a clamp for vertically aligning poles which provides swinging pointers with scales for determining the plumb position, and also provides for off-setting the pointers from the center of the clamp to provide for irregularities in the pole. This device however fails to provide for extending the length of the device to facilitate the plumbing of longer vertical surfaces, nor does it provide for measuring the degree of tolerance, or for measuring the degree of rotation of a pile. The present device is further distinguishable in that it provides for a modular assembly, which can be dissembled with relative ease for ready storage. Additionally, the present invention provides for a much simpler operation in determining the plumbness of a vertical surface.
Another earlier device U.S. Pat. No. 700,326 to Hamel discloses a combined level-protractor, square and pitch board. It provided a scale plate pivotally mounted to a blade member held in position by a thumb nut. The device also provided a bubble level attached to the scale plate. The present invention is an improvement upon this device in that it provides for the attachment of spacer members to bridge distortions in a vertical surface, and provides interchangeable extension members to be attached to the device for increasing its length. It further provides a second scale for determining tolerances from vertical plumb, and a compass for determining whether any rotation has been realized.
It is believed that there are no devices in the prior art which are capable of providing the features of the present invention. Further advantages and improvements over the aforementioned references will become apparent from the discussion that follows.